1. Field of the Invention
This invention relates generally to bottom connectors for tension leg platform tendons, and more particularly to a method for positive locking of a tension leg platform tendon bottom connector in a receptacle.
2. Background Art
The bottom connectors typically used on the tendons of tension leg platforms (TLP) make connection to specially profiled connection sleeves (also known as receptacles) that are incorporated into the upper portion of the tendon foundation piles. It has been common practice to design tendon bottom connectors that are locked and unlocked with the receptacle by means of vertical motion. The typical lock function is for the bottom connector to be inserted into the pile, and locking with the receptacle is achieved by a vertical downstroke, sometimes with an upstroke after the initial downstroke. The typical unlock function is to downstroke the bottom connector with mechanical elements of the bottom connector to cause an unlock condition and release to occur with subsequent upward motion.
Accepted practice has been to design the tension leg platform (TLP) in such a fashion that the expected tendon bottom tension will either stay positive, preventing downstroke and subsequent release activation, or only slightly negative, allowing insufficient downstroke to begin the subsequent release activation.
The following U.S. patents are exemplary of conventional tendon bottom connectors for use with tension leg platforms, all of which are hereby incorporated by reference to the same extent as if fully set forth herein.
Owens, U.S. Pat. No. 4,611,953
Hunter, et al, U.S. Pat. No. 4,848,970
Gunderson, et al, U.S. Pat. No. 4,907,914
Peppel, U.S. Pat. No. 4,943,188
Kipp, U.S. Pat. No. 5,004,272
Hunter, et al, U.S. Pat. No. 5,324,141
Paulshus, et al, U.S. Pat. No. 6,568,875
Pallini, Jr., et al, U.S. Pat. RE 38,458
The patents listed above show and describe various conventional tendon bottom connectors and tendon receptacles having various types of mating latching or locking and release mechanisms. It should be understood that the present invention is directed toward a method for positive locking of a tension leg platform tendon bottom connector in a tendon receptacle contained in a tendon foundation pile, and may be utilized with conventional tendon bottom connectors and receptacles of various construction wherein release of the locking elements is accomplished by vertical motion of the bottom connector. The patents listed above do not disclose the present method for positive locking of the tendon bottom connector as set forth herein. The reader may refer to the above patents for a more comprehensive detailed description of the structural components of tendon bottom connectors, their latching or locking and release components, and their operation.
The present invention is distinguished over the prior art in general by a method for positive locking of a tension leg platform tendon bottom connector in a tendon receptacle contained in a tendon foundation pile, the bottom connector and receptacle having mating locking elements. A vertical space is provided in the foundation pile between the tendon receptacle and the soil level inside the pile sufficient to allow vertical entry and locking of the bottom connector and receptacle locking elements, and a material of sufficient density is placed into the space beneath the tendon bottom connector in the tendon receptacle and the soil level inside the pile to limit downward vertical motion of the bottom connector and prevent accidental release of the locking elements. When required, a sufficient amount of the material may be removed to allow the requisite vertical motion of the bottom connector to release the locking elements.